This invention pertains to an improved type hand operated metal shear, commonly called snips, that will smoothly cut flat or curved metal such as corrugated roofing.
Present hand operated shears operate to cut metal in much the same way as scissors cut cloth. Problems arise because the rigid metal interferes with forward motion of the shears and cutting along a predetermined line for several feet becomes quite difficult.
Present power driven shears sometimes called "nibblers" overcome the problem with common hand operated shears by removing approximately a one fourth inch wide portion of metal so as to leave approximately 1/4" opening for the support shaft of the "nibbler" cutting mechanism to move between the pieces of metal being cut. In general these are too expensive for the normal "once in awhile" use and generally are so shaped as to operate poorly when cutting curved metal such as corrugated roofing.
There is a need for a low cost hand operated metal shear or "snips" that will cut flat or curved metal without the necessity of distorting the metal being cut to accommodate the shear.
There have been attempts to develop such a hand operated metal shear that remove a strip of metal in pieces or as a strip. These did not work as well as the subject invention because of various problems one of which usually was that the mechanism used to remove the metal fit too tightly between the parent metal to allow free movement to cut along a predetermined line. In general they worked only on flat surfaces and for cutting only a short distance.
There is a need for hand operated metal shears that will smoothly:
1. cut flat or curved surfaces;
2. cut straight, cut curving to right or left, or cut out odd shapes such as elliptical shapes;
3. and be low cost and of durable construction.
The invention as described in the following pages, drawings and claims effectively meets these objectives.
We have considered the following patents in this field:
______________________________________ U.S. Pat. No. Date Inventor ______________________________________ 596,546 1898 W. T. Runyan 1,812,350 1931 F. D. Lingwood 3,362,071 1968 C. C. Schmidt 375,555 1887 S. Loffer 170,658 1875 T. Berridge 2,357,197 1943 A. J. Hoop ______________________________________